TW202532005A - Zipper chain cloth, zipper having the same, and method for manufacturing the zipper chain cloth - Google Patents

Abstract

The present invention is a zipper fabric (10) comprising a base fabric (11, 32) and a water-stop film (12, 33) attached to at least one side of the base fabric (11, 32), wherein the water-stop film (12, 33) has a layered structure comprising: a surface layer (13) comprising a film made of water-based polyurethane produced by an acetone method; and a bonding layer (14) adjacent to the surface layer (13) and comprising a cured product containing a bonding agent of water-based polyurethane produced by an acetone method.

Description

Zipper fabric, zipper having the same, and method for manufacturing the zipper fabric

The present invention relates to a waterproof zipper fabric, a zipper having the waterproof zipper fabric, and a method for manufacturing the waterproof zipper fabric.

Zippers are widely used as fasteners for everyday items such as clothing, bags, shoes, and sundries. They are also used in protective clothing such as space suits, chemical protective suits, diving suits, life jackets, and transport container covers and tents. For these specialized applications, zippers also need to be waterproof.

A zipper generally consists of three main components: a pair of long zipper fabrics; zipper teeth, which are the engaging portion of the zipper sewn along one side of each fabric; and a slider, which controls the opening and closing of the zipper by engaging and disengaging the teeth. Previously, zippers were known that, to impart waterproof properties, adhered a waterproof synthetic resin film to the zipper fabrics. When the zipper is closed, the synthetic resin films on the left and right zipper fabrics come into close contact, thereby achieving waterproof properties. Polyurethane films are commonly used as synthetic resin films.

In recent years, the industry has increasingly demanded that products be manufactured with consideration for the environmental impact and worker health of organic solvents. Consequently, there is a desire for waterproof zippers to transition to environmentally conscious zippers that reduce the use of organic solvents. International Publication No. 2014/010019 (Patent Document 1) discloses a zipper fabric with a water-based polyurethane film bonded to it via a water-based polyurethane adhesive. In the examples of Patent Document 1, RESAMINE D from Dainichi Seika Co., Ltd. is used as the water-based polyurethane adhesive and the water-based polyurethane film. Prior Art Patent Document

Patent Document 1: International Publication No. 2014/010019

[Identify the problem you want to solve]

The production methods for water-based polyurethanes include the forced emulsification method and the self-emulsification method. RESAMINE D used in the examples of Patent Document 1 is produced by the pre-polymerization forced emulsification method and is provided as an aqueous polyurethane dispersion. In the pre-polymerization forced emulsification method, N-methylpyrrolidone (NMP) is often used as a viscosity modifier during the polyurethane production process, and it tends to remain in the polyurethane aqueous dispersion. However, in recent years, NMP has been added as a regulated substance in the European REACH (Registration, Evaluation, Authorization and Restriction of Chemicals) regulations, leading to the desire to use environmentally conscious water-based polyurethanes that do not use NMP in the production process.

On the other hand, waterproof zippers also require practicality such as good adhesion between the waterproof membrane and the base fabric that constitutes the zipper chain, and durability when the zipper is opened and closed.

In view of the above, one object of the present invention is to provide a zipper fabric having excellent environmental performance and being practical for use as a waterproof zipper. Furthermore, another object of the present invention is to provide a zipper incorporating such a zipper fabric. Furthermore, another object of the present invention is to provide a method for manufacturing such a zipper fabric. [Technical Means for Solving the Problem]

The inventors of the present invention have conducted intensive research to solve the above problems and have found that using water-based polyurethane produced by the acetone method for waterproof membranes and adhesives is effective.

[Aspect 1] A zipper fabric comprises a base fabric and a water-stop film attached to at least one surface of the base fabric. The water-stop film has a laminated structure comprising: a surface layer comprising a film made from a water-based polyurethane produced by an acetone method; and an adhesive layer, adjacent to the surface layer, comprising a cured adhesive containing a water-based polyurethane produced by an acetone method. [Aspect 2] The zipper fabric according to Aspect 1, wherein both the water-based polyurethane used as a raw material for the film and the water-based polyurethane contained in the adhesive contain a polycarbonate-based polyurethane. [Aspect 3] The zipper fabric according to Aspect 1 or 2, wherein the adhesive is a two-component adhesive that cures by mixing at least a water-based polyurethane having a hydroxyl group produced by an acetone method as a base agent and an isocyanate compound as a curing agent. [Aspect 4] The zipper fabric according to Aspect 3, wherein the water-based polyurethane having a hydroxyl group produced by an acetone method as a base agent contains a polycarbonate-based polyurethane having a hydroxyl group. [Aspect 5] The zipper chain fabric according to Aspect 4, wherein the cured adhesive is obtained by mixing at least a base agent and a curing agent such that the molar ratio (NCO/OH) of the isocyanate group (NCO) of the curing agent to the hydroxyl group (OH) of the water-based polyurethane compound (OH) of the base agent is 1.4 or greater. [Aspect 6] The zipper fabric according to any of Aspects 1 to 5, wherein the water-based polyurethane used as the raw material for the membrane, produced by the acetone method, is a mixture of a low molecular weight water-based polyurethane having a weight average molecular weight of 7,000 to 15,000 and a high molecular weight water-based polyurethane having a weight average molecular weight of 18,000 to 32,000, in a mass ratio of low molecular weight water-based polyurethane to high molecular weight water-based polyurethane of 5:95 to 20:80. [Aspect 7] A zipper comprising the zipper fabric according to any of Aspects 1 to 6. [Aspect 8] A method for manufacturing a zipper fabric comprises the following steps: Laminating a surface layer comprising a film made from a water-based polyurethane produced by an acetone method to a base fabric via an adhesive containing a water-based polyurethane produced by an acetone method; and Curing the adhesive interposed between the surface layer and the base fabric. [Aspect 9] The method for manufacturing a zipper fabric according to Aspect 8, wherein both the water-based polyurethane used as a raw material for the film and the water-based polyurethane contained in the adhesive contain a polycarbonate-based polyurethane. [Aspect 10] The method for producing a zipper fabric according to Aspect 8 or 9, wherein the adhesive is a two-component adhesive that is cured by mixing at least a water-based polyurethane having a hydroxyl group produced by an acetone method as a main agent and an isocyanate compound as a hardener. [Aspect 11] The method for producing a zipper fabric according to Aspect 10, wherein the water-based polyurethane having a hydroxyl group produced by an acetone method as a main agent contains a polycarbonate-based polyurethane having a hydroxyl group. [Aspect 12] The method for manufacturing a zipper chain fabric as described in Aspect 11, wherein the cured adhesive is obtained by mixing at least a base agent and a curing agent such that the molar ratio (NCO/OH) of the isocyanate group (NCO) of the curing agent to the hydroxyl group (OH) of the water-based polyurethane compound (OH) of the base agent is 1.4 or greater. [Aspect 13] A method for producing a zipper fabric as described in any of Aspects 8 to 12, wherein the water-based polyurethane adhesive used as a raw material for the membrane, produced by the acetone method, is obtained by mixing a low molecular weight water-based polyurethane having a weight average molecular weight of 7,000 to 15,000 and a high molecular weight water-based polyurethane having a weight average molecular weight of 18,000 to 32,000 in a mass ratio of low molecular weight water-based polyurethane to high molecular weight water-based polyurethane = 5:95 to 20:80. [Effects of the Invention]

Waterborne polyurethanes produced using the acetone process are virtually free of residual organic solvents, such as NMP, which poses a high environmental burden. Acetone not only has a lower environmental burden, but also, due to its low boiling point, can be easily removed from the polyurethane via a distillation step, making it easily recyclable and reusable.

Furthermore, water-based polyurethane produced via the acetone method can be used as an adhesive between the waterproof membrane and the base fabric of zipper zippers, providing excellent adhesion and chemical resistance. Furthermore, in preferred embodiments, it exhibits excellent durability during reciprocating opening and closing when used in zippers. While not intending to be bound by theory, this is presumably due to the following reasons. The acetone method allows for control of the polyurethane molecular weight in an acetone solvent, resulting in a polyurethane with a more uniform particle size distribution than pre-polymerization methods using NMP. Although polyurethane is ultimately provided as a dispersion in water (water-based polyurethane), its highly uniform particle size distribution improves the homogeneity of the polyurethane particles as they bond together during heating to remove water. This contributes to improved bond strength and durability during reciprocating opening and closing. Furthermore, when water-based polyurethane produced via the acetone method is used for both the waterproof membrane and the adhesive, the high compatibility between the two contributes to a stronger bond between the waterproof membrane and the base fabric.

However, the mechanism of the effects achieved by using water-based polyurethanes is based on inference, and clarifying the cause requires advanced analytical techniques and a long time. Therefore, in this manual, the water-based polyurethane used is specified according to the preparation method.

Figure 1 shows the laminated structure of a zipper fabric for a zipper according to one embodiment of the present invention. Zipper fabric 10 comprises a base fabric 11 and a waterproof membrane 12 attached to at least one side of base fabric 11. Waterproof membrane 12 has a laminated structure comprising: a surface layer 13 made of a water-based polyurethane produced by the acetone method; and an adhesive layer 14, adjacent to surface layer 13, comprising a cured adhesive containing the water-based polyurethane produced by the acetone method. Specifically, the zipper fabric 10 includes a bonding layer 14 on the base fabric 11 side of the surface layer 13, and the bonding layer 14 connects the base fabric 11 and the surface layer 13. Thus, as shown in FIG1 , the zipper fabric 10 has a layered structure in which, from the upper side in the drawing, the surface layer 13, the bonding layer 14, and the base fabric 11 are layered in this order.

(1. Base Fabric) The base fabric 11 can be made of natural or synthetic fibers commonly used in zipper fabrics, without particular limitation. Examples include polyamide fibers, polyester fibers, and acrylic fibers. The base fabric 11 can be made by weaving or knitting one or more of these synthetic fibers. Typically, it is woven or knitted from polyester fibers.

An example of the steps for attaching the waterproof film 12 to the base fabric 11 is described below. A cured product of the surface layer 13 of the waterproof film 12 is prepared, and an adhesive is applied to its surface and then heated and dried. Drying can be carried out, for example, in a constant temperature bath or an infrared dryer. There is no limit to the drying conditions, but when drying in a constant temperature bath, for example, it is preferably set to 70 to 90°C for 5 to 8 minutes, and when drying in an infrared dryer, it is preferably set to 70 to 90°C for 4 to 8 minutes. In the case of a low moisture content, that is, due to excessive heating and drying, the curing reaction is advanced, the adhesive is polymerized, and thus the bonding force used to attach the film is lost. In contrast, higher moisture contents in the adhesive layer cause the adhesive to contain more water, so the water won't be removed after film lamination, resulting in poor appearance (internal bubbles). For these reasons, the moisture content of the adhesive after drying is preferably 1-8% by mass. In particular, when drying in a constant temperature oven, the moisture content is preferably 1.5-3.5% by mass, more preferably 2.0-3.0% by mass, and even more preferably 2.5% by mass. When drying in an infrared dryer, the moisture content is preferably 2.0-6.0% by mass, more preferably 2.0-4.0% by mass. The moisture content of the adhesive is determined by measuring the weight difference of the recovered adhesive-coated film before and after drying. Specifically, it is expressed as: Adhesive Moisture Content (%) = (Mass of Adhesive-coated Film Before Drying - Mass of Adhesive-coated Film After Drying) / (Mass of Adhesive-coated Film Before Drying) × 100. Next, heat and pressure are applied to the adhesive layer 14 of the waterproof film 12 (the adhesive-coated side) while the adhesive layer 14 serves as the bonding surface and is bonded to at least one side of the base fabric 11 (a step of bonding the surface layer 13 to the base fabric 11) (temporarily bonded). Next, the curing agent is cured by accelerating the curing reaction at room temperature, for example, 18-28°C for 30-40 hours (e.g., 36 hours at 23°C), or 45-55°C for 20-30 hours (e.g., 24 hours at 50°C). This curing step securely bonds the base fabric 11 to the waterproof membrane 12. The curing atmosphere can be air. This results in a waterproof zipper fabric 10. Alternatively, the adhesive can be applied to the base fabric 11.

(2. Adhesive Layer) The adhesive layer 14 is formed from a cured product containing an adhesive comprising a water-based polyurethane (polyurethane and water as a dispersion medium) produced by the acetone method. The adhesive is preferably a two-component adhesive, which is cured by mixing at least a water-based polyurethane having a hydroxyl group produced by the acetone method as a base agent and an isocyanate compound as a curing agent. In water-based polyurethanes, typically, fine particles of polyurethane are dispersed in water, for example, in the form of a polyurethane emulsion or polyurethane dispersion. Here, "water-based" means using water as the dispersion medium.

Water-based polyurethane produced by the acetone method is a self-emulsifying type of polyurethane. Due to the introduction of hydrophilic groups, it is provided as polyurethane microparticles dispersed in water. In the acetone method, the polyurethane is subjected to a high molecular weight in an acetone solvent, dispersed in water, and then deacetoneized. It is believed that since molecular weight control in an acetone solvent is relatively easy, a polyurethane with high molecular weight uniformity is obtained. Furthermore, this high molecular weight uniformity is speculated to contribute to improved bonding strength and reciprocating opening and closing durability. In one embodiment, the polydispersity index (Mw/Mn), the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn), of the water-based polyurethane produced by the acetone method is 2.0 or less. The polydispersity index (Mw/Mn) of waterborne polyurethane produced by the acetone method is preferably 1.8 or less, more preferably 1.6 or less. While there is no specific lower limit for the polydispersity index (Mw/Mn) of waterborne polyurethane produced by the acetone method, 1.0 is ideal. However, for ease of production and storage stability, a range of 1.2-2.0 is preferred, with a range of 1.4-1.8 being more preferred. To ensure adhesion (tackiness) after coating and improve the initial adhesion strength of the adhesive layer to the zipper fabric, the weight-average molecular weight (Mw) of waterborne polyurethane produced by the acetone method is preferably 2000-6000, more preferably 3000-5000.

Any water-based polyurethane known to practitioners can be used as the water-based polyurethane produced by the acetone method, but polyether polyurethane, polyester polyurethane, polycarbonate polyurethane, or polycaprolactone polyurethane having a hydrophilic group is preferred. Among these, polycarbonate polyurethane having a hydrophilic group is more preferred due to its hydrolysis resistance, heat resistance, oil resistance, and abrasion resistance. The hydrophilic group can be a cationic, anionic, or nonionic hydrophilic group, which can be used alone or in combination. Examples of cationic groups include amino groups. Examples of anionic hydrophilic groups include carboxyl groups, phosphonic acid groups, and sulfonic acid groups. Examples of non-ionic hydrophilic groups include polyoxyalkylene groups (e.g., polyethylene oxide) and hydroxyl groups. Among these hydrophilic groups, it is preferred to have at least a hydroxyl group to promote the curing reaction with the curing agent. Furthermore, in the case of anionic hydrophilic groups such as carboxyl groups, neutralization with a base such as triethylamine, ammonia, or 2-amino-2-methylpropanol is preferred to enhance the hydrophilicity of the polyurethane.

The isocyanate compound used as a hardener may contain an aliphatic isocyanate, an alicyclic isocyanate, an aromatic isocyanate, or a combination of two or more thereof. Isocyanates can be selected, for example, from dimers, trimers, isocyanate derivatives, isocyanate prepolymers, and blocked isocyanates. Aromatic isocyanates tend to yellow, while aliphatic isocyanates, alicyclic isocyanates, or a combination thereof have excellent discoloration resistance and a longer pot life (also known as usable time, which is the time from when the viscosity or state of the adhesive becomes unbearable after a hardener or catalyst is mixed into the adhesive). Therefore, it is preferred to use an aliphatic isocyanate, alicyclic isocyanate, or a combination thereof. Examples of aliphatic isocyanates include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 2,2,4-trimethylhexane diisocyanate, lysine diisocyanate, 2,6-diisocyanatomethylhexanoate, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, bis(isocyanatomethyl)cyclohexane, cyclohexylene diisocyanate, and methylcyclohexylene diisocyanate. These can be provided as monomers or as polymers.

A thickener may be added to the adhesive for purposes such as improving coatability. Any known water-soluble thickener may be used, including natural polymers such as polysaccharides and gelatin, synthetic polymers such as hydrophobically modified ethoxylated urethanes, polyethylene oxide, and cross-linked poly(meth)acrylic acid, and inorganic minerals such as montmorillonite and silica.

During curing, the water-based polyurethane adhesive undergoes solvent evaporation and a reaction between the main agent and the hardener. The resulting adhesive layer 14 primarily comprises crosslinked polyurethane formed by the curing reaction between the main agent and the hardener, and its solid components in the presence of a tackifier. When forming the adhesive layer 14, the mixing ratio of the main agent and the hardener is preferably set to achieve the desired bonding strength. Specifically, the base and curing agents are preferably mixed so that the molar ratio (NCO/OH) of the isocyanate group (NCO) of the curing agent to the hydroxyl group (OH) of the waterborne polyurethane (waterborne polyurethane) of the base is 1.0 or greater. More preferably, the molar ratio is 1.2 or greater, and even more preferably, 1.4 or greater. Furthermore, from the perspective of preventing appearance abnormalities caused by side reactions, the NCO/OH ratio is preferably 3.0 or less, more preferably 2.5 or less, and even more preferably 2.0 or less. Therefore, NCO/OH is preferably 1.0 to 3.0, more preferably 1.2 to 2.5, and even more preferably 1.4 to 2.0.

In order to improve the adhesion between the waterproof membrane and the base fabric, the amount of hydroxyl groups (OH) in the water-based polyurethane as the main agent, expressed as the mass concentration of the polyurethane solid content in the water-based polyurethane as the main agent, is preferably 1.0 mass% or more, more preferably 1.3 mass% or more, and even more preferably 1.6 mass% or more. On the other hand, considering the balance between strength and softness of the adhesive layer, the amount of hydroxyl groups (OH) in the water-based polyurethane as the main agent, expressed as the mass concentration of the polyurethane solid content in the water-based polyurethane as the main agent, is preferably 3.0 mass% or less, more preferably 2.5 mass% or less, and even more preferably 2.0 mass% or less. Therefore, the amount of hydroxyl groups (OH) in the water-based polyurethane as the main agent, expressed as the mass concentration of the polyurethane solid content in the water-based polyurethane as the main agent, is preferably, for example, 1.0-3.0 mass%, more preferably 1.3-2.5 mass%, and even more preferably 1.6-2.0 mass% or less.

In this specification, the amount of hydroxyl (OH) groups in water-based polyurethanes is determined using the following procedure. 2-Naphthyloxyacetyl chloride is used as a UV (Ultraviolet) labeling reagent and reacted with the water-based polyurethane in tetrahydrofuran (THF) in the presence of pyridine for approximately 24 hours. Subsequently, gel permeation chromatography (GPC) is performed, and the amount of hydroxyl (OH) groups is determined using a calibration curve method based on the peak area at the UV absorption wavelengths inherent to the labeling reagent (near 240 nm, 270 nm, and 330 nm). In this specification, the amount of isocyanate groups (NCO) in an isocyanate compound is determined by adding an excess of di-n-butylamine to the isocyanate compound to cause a reaction, and then neutralizing and titrating the remaining di-n-butylamine with hydrochloric acid.

For reasons of durability during reciprocating opening and closing, the thickness of the adhesive layer 14 is preferably 50 μm or greater, more preferably 70 μm or greater, and even more preferably 90 μm or greater. On the other hand, if the adhesive layer 14 is too thick, the slider may slide and contact during the zipper opening and closing, impairing slidability. Therefore, it is preferably 150 μm or less, more preferably 120 μm or less, and even more preferably 100 μm or less. Therefore, the thickness of the adhesive layer 14 is preferably 50 μm or greater and 150 μm or less, more preferably 70 μm or greater and 120 μm or less, and even more preferably 90 μm or greater and 100 μm or less.

In this specification, the thickness of the bonding layer 14 is measured by the following method. The overall thickness of the zipper fabric is measured at three locations near the center in the width direction at intervals of 8 to 10 cm in the length direction. The thickness is measured using a digital thickness gauge. The average value of the thickness obtained at the three locations is calculated. Next, at the same location as the location where the overall thickness of the zipper fabric was measured, the thickness of the base fabric and the surface layer obtained by removing the bonding layer from the zipper fabric is measured using the same method, and the average value of the thickness of the base fabric and the surface layer is calculated. Then, the total value obtained by subtracting the average value of the thickness of the base fabric and the surface layer from the average value of the overall thickness of the zipper fabric is used as the thickness of the bonding layer.

(3. Skin Layer) The skin layer 13 can be formed from a membrane made from a water-based polyurethane produced using the acetone method. This membrane can be obtained by heat-drying a liquid containing water-based polyurethane, typically a dispersion of fine particles of polyurethane in water. Drying conditions are not limited, but for example, drying can be performed in a hot air drying oven at 50-90°C for 3-10 minutes.

Water-based polyurethane produced via the acetone method is a self-emulsifying polyurethane. Due to the introduction of hydrophilic groups, it is provided as polyurethane microparticles dispersed in water. As mentioned above, water-based polyurethane produced via the acetone method is believed to have a higher molecular weight uniformity. This higher molecular weight uniformity is speculated to contribute to improved adhesive strength and reciprocating opening and closing durability.

The water-based polyurethane produced by the acetone method can be any of those known to practitioners, preferably polyether polyurethane, polyester polyurethane, polycarbonate polyurethane, or polycaprolactone polyurethane having a hydrophilic group. Among these, polycarbonate polyurethane having a hydrophilic group is more preferred due to its hydrolysis resistance, heat resistance, oil resistance, and abrasion resistance. The hydrophilic group can be a cationic, anionic, or nonionic hydrophilic group, which can be used alone or in combination. Examples of cationic groups include amino groups. Examples of anionic hydrophilic groups include carboxyl groups, phosphonic acid groups, and sulfonic acid groups. Examples of non-ionic hydrophilic groups include polyalkylene oxides (e.g., polyethylene oxide) and hydroxyl groups. Among hydrophilic groups, anionic hydrophilic groups are preferred. Furthermore, in the case of anionic hydrophilic groups such as carboxyl groups, neutralization with a base such as triethylamine, ammonia, 2-amino-2-methylpropanol, or 2-dimethylaminoethanol is preferred to enhance the hydrophilicity of the polyurethane.

Water-based polyurethanes with a weight-average molecular weight of 7,000 to 32,000 are suitable. To achieve a film with excellent strength even after a short heat drying time, a mixture of a low-molecular-weight water-based polyurethane with a weight-average molecular weight of 7,000 to 15,000 and a high-molecular-weight water-based polyurethane with a weight-average molecular weight of 18,000 to 32,000 is preferred. The weight ratio of the low-molecular-weight water-based polyurethane to the high-molecular-weight water-based polyurethane is preferably 5:95 to 20:80, more preferably 10:90 to 15:85, to improve film strength. The weight average molecular weight of waterborne polyurethane can be determined by GPC (molecular weight distribution).

A thickening agent may be added to the film forming the epidermal layer 13 for purposes such as ease of forming and processing. Any known water-soluble thickening agent may be used, including, for example, natural polymers such as polysaccharides and gelatin, synthetic polymers such as hydrophobically modified ethoxylated urethanes, polyethylene oxide, and cross-linked poly(meth)acrylic acid, and inorganic minerals such as montmorillonite and silica.

(4. Zipper Implementation) Figures 2 through 4 illustrate an example of a waterproof zipper 20 incorporating the zipper fabric of the present invention. Figure 2 is a top view of the entire waterproof zipper 20, Figure 3 is a cross-sectional view showing the zipper chain teeth 21 engaged within a slider 22, and Figure 4 is a perspective cross-sectional view of a portion of the waterproof zipper 20. Along one side of the base fabric 11 of each zipper fabric 10, a linear, buckle-shaped zipper chain tooth 21, with a core cord 23 inserted therethrough, is sewn using double-stitching seams 24 on a sewing machine. The buckle-shaped zipper chain teeth 21 can be formed from monofilaments of a synthetic resin such as polyamide or polyester. The waterproof membrane 12 of the pair of zipper fabrics 10 can be bonded to the fabric of the article using an adhesive. Alternatively, the waterproof membrane 12 can be welded to the fabric using high-frequency welding, or sewing can be performed. A slider is inserted between the left and right chain teeth, and the zipper's opening and closing can be controlled by sliding the slider. The seam 24 can also be treated with a water-repellent finish.

The side edges of the waterproof membrane 12, relative to the base fabric 11, extend toward the centerline A of the toothed chain. This facilitates close contact between the left and right waterproof membranes 12, improving waterproofing. If the side edges of the waterproof membrane 12 extend slightly beyond the centerline A of the toothed chain, the left and right waterproof membranes 12 will be in close contact when the left and right toothed chains are engaged, achieving even higher waterproofing.

When using the waterproof zipper 20 of this embodiment, it is preferably installed on the object with the side with the waterproof film 12 attached as the outer surface and the side with the zipper teeth 21 as the inner surface. The pull tab 25 of the slider 22 can be attached to the outer surface. Furthermore, an upper stop 26 can be provided as shown in Figure 2. Although not shown, a lower stop or a detachable insert can also be installed.

Figures 5 and 6 show partial schematic views of another embodiment of a waterproof zipper according to the present invention. Specifically, Figure 5 shows a portion of a zipper tape 27 constituting the waterproof zipper according to this embodiment, while Figure 6 is a cross-sectional view imaginarily illustrating the state in which left and right zipper teeth 28 of the zipper according to this embodiment are engaged within a slider 29.

In this alternative embodiment, as shown in Figures 5 and 6 , the zipper teeth 28 are injection-molded as a single unit, sandwiching a core 31 formed at the end edges of a zipper fabric 30 from the front and back. The slider 29 is represented by an imaginary single-point chain line. The zipper fabric 30 is formed by attaching a waterproof film 33 to the outer surface of a base fabric 32. Furthermore, as shown in Figure 6 , when the zipper teeth 28 are engaged, the leading end of the zipper teeth 28 on one side (the end facing the zipper fabric 30 on the other side) is in close contact with the zipper fabric 30 on the other side, thereby achieving waterproof properties.

Waterproof zippers can be used for a variety of special applications, including protective clothing such as space suits, chemical protective suits, diving suits, life jackets, and containers, as well as covers for transport containers and tents. They can also be used as closures for everyday items such as clothing (especially rain gear), bags, shoes, and sundries. [Examples]

In order to better understand the present invention and its advantages, embodiments are shown below, but the present invention is not limited to these embodiments.

(1. Materials) The materials used in each test example are as follows. (A) Water-based polyurethane (all produced by the acetone method) [A-1] IMPRANIL (registered trademark) DLC-F: Manufactured by Covestro Corporation, an anionic polyurethane dispersion based on polycarbonate (solid content = approximately 40% by mass, weight-average molecular weight = 25,000), containing carboxyl groups as anionic hydrophilic groups. [A-2] Bayhydrol (registered trademark) UH2648/1: Manufactured by Covestro Corporation, an anionic polyurethane dispersion based on polyester-polycarbonate (solid content = approximately 35% by mass, weight-average molecular weight = 11,000), containing carboxyl groups as anionic hydrophilic groups. [A-3] Bayhydrol (registered trademark) U2757: Covestro Corporation, hydroxyl-functional polycarbonate-based polyurethane aqueous dispersion (solids content = approximately 53 mass%, OH group content = approximately 1.0 mass%, weight-average molecular weight = 4,000, polydispersity index (Mw/Mn) = 1.6) (B) Isocyanate compound (hardener) Bayhydur (registered trademark) XP 2547: Covestro Corporation, mixture of hexamethylene-1,6-diisocyanate homopolymer (80 mass%) and HDI (hexamethylene diisocyanate)-based hydrophilic aliphatic polyisocyanate (20 mass%) (NCO group content = 22.5 mass%) (C) Thickener Rheovis (registered trademark) PU1341: BASF's hydrophobically modified ethoxylated urethane (HEUR)

(2. Zipper Chain Fabric Production) Use the above materials according to the following steps to produce each zipper chain fabric. Mix the materials listed in the "Surface Layer" column of Table 1 according to the test number and the ratio listed in Table 1. Apply the mixture to the release film and heat-dry in air at 90°C for 5 minutes in a constant temperature oven to obtain a surface layer film with a thickness of 35-45 μm. Next, the materials listed in the "Adhesive Layer" column of Table 1 (two-component adhesive) were mixed according to the test number and the ratio listed in Table 1. The mixture was then applied to the surface of the skin layer and dried in a constant temperature bath at 90°C in air for 5 minutes. The moisture content of the dried adhesive was measured using the above method and found to be 1.8% by mass. A zipper chain fabric woven from polyester yarn was attached to the adhesive using a rubber roller (Schönler hardness 50-95°) under pressure (4 MPa). The curing reaction was then accelerated in a constant temperature bath at 50°C in air for 24 hours. In this manner, zipper fabrics with waterproof film attached were produced. The thickness of the adhesive layer was measured using samples of this zipper fabric using the aforementioned method. The results are reported in Table 1.

[Table 1] Epidermis Next layer Test number Material Mixing ratio (mass) Material Mixing ratio (mass) NCO/OH (molar ratio) Thickness (μm) 1 A-1:IMPRANIL DLC-F 90.0 A-3: Bayhydrol U2757 100.0 0.8 100 A-2: Bayhydrol UH2648/1 10.0 B: Bayhydur XP 2547 8.8 C:Rheovis PU1341 1.0 C:Rheovis PU1341 2.0 2 A-1:IMPRANIL DLC-F 90.0 A-3: Bayhydrol U2757 100.0 1.0 100 A-2: Bayhydrol UH2648/1 10.0 B: Bayhydur XP 2547 11.0 C:Rheovis PU1341 1.0 C:Rheovis PU1341 2.0 3 A-1:IMPRANIL DLC-F 90.0 A-3: Bayhydrol U2757 100.0 1.2 100 A-2: Bayhydrol UH2648/1 10.0 B: Bayhydur XP 2547 13.2 C:Rheovis PU1341 1.0 C:Rheovis PU1341 2.0 4 A-1:IMPRANIL DLC-F 90.0 A-3: Bayhydrol U2757 100.0 1.5 100 A-2: Bayhydrol UH2648/1 10.0 B: Bayhydur XP 2547 16.5 C:Rheovis PU1341 1.0 C:Rheovis PU1341 2.0

(3. Performance Evaluation)

[3-1. Acetone Resistance Test A] Immerse the zipper fabrics prepared above in acetone (at room temperature) for 1 minute. Then, remove the fabrics and evaluate for any peeling of the water-stop film. After the test, if any peeling exceeding 1 mm and less than 1.5 mm in length was observed along the length of the fabric, a score of "D" was assigned. If any peeling exceeding 0.5 mm and less than 1.5 mm was observed along the length of the fabric, a score of "C" was assigned. If there was little film peeling, but some areas that could be considered abnormal were observed, a score of "B" was assigned. If no abnormalities were observed, a score of "A" was assigned. The results are shown in Table 2.

[3-2. Acetone Resistance Test B] Using the zipper fabrics prepared above for each test number, a waterproof zipper with a MH-class width (as shown in Figure 2) was assembled and immersed in acetone (at room temperature) for 10 seconds. After the waterproof zipper was lifted, a reciprocating opening and closing durability test was conducted 5 minutes later, using the slider to slide 10 times. Following the test, the surface film was visually inspected for any abnormalities (e.g., peeling of the surface film). The evaluation criteria were the same as for Acetone Resistance Test A. The results are shown in Table 2.

[3-3. Reciprocating Opening and Closing Durability Test] Using the zipper fabrics prepared above, the waterproof zipper with a chain width of MH class (as shown in Figure 2) was assembled. The zipper was opened and closed 500 times, 1000 times, 1500 times, and 2000 times, respectively, under a normal temperature and humidity environment of 20°C and a relative humidity of 65%. The reciprocating opening and closing durability test was conducted in accordance with JIS S 3015(2019). Furthermore, the reciprocating opening and closing durability test was conducted 100 times under a high temperature and humidity environment of 70°C and a relative humidity of 95%. After the test, the surface film was visually inspected for any abnormalities (e.g., peeling of the surface film). The slider travel distance per slide was set to 50 mm. The evaluation criteria were the same as for the acetone resistance test A. The results are shown in Table 2.

(4. Evaluation of Adhesive Processability) [4-1. Touchdown] The touchdown properties of the two-component adhesives used in the adhesive layer of the zipper fabrics of each test number were evaluated using the following method. Using a coating machine, the adhesive was applied to a release paper sheet conveyed at a constant speed in an atmosphere of constant temperature at a thickness of approximately 230 μm over a length of 30 cm. In the case of materials with high touchdown properties, the liquid transformed into a non-flowing gel shortly after application, resulting in poor continuous coating performance. The evaluation criteria were "Good" if the coating was consistently and evenly applied, and "Poor" if uncoated areas were observed intermittently. The results are shown in Table 2.

[4-2. Leveling] Leveling properties were evaluated for each two-component adhesive used in the adhesive layer of each zipper fabric using the following method. The adhesive was applied to a release paper sheet conveyed at a constant speed using a coating machine in an atmosphere of constant temperature. After application, the adhesive was dried at 90°C for 5 minutes to obtain a bonded layer. The resulting release paper with the adhesive layer was cut into a 30 cm x 30 cm square. Using a Mitutoyo Co., Ltd. model 547-401A digital thickness gauge (1 μm accuracy), the thickness was measured near the edges of two adjacent sides (vertical and horizontal). Three measurements were taken on each side, approximately 9 cm apart (a total of six locations). The evaluation criteria were as follows. The results are shown in Table 2. Good: ... The difference between the maximum and minimum thickness values at all six locations was less than 3 μm. Acceptable: ... The difference between the maximum and minimum thickness values at all six locations was 3 μm or more and less than 7 μm. Unacceptable: ... The difference between the maximum and minimum thickness values at all six locations was 7 μm or more.

[4-3. Foaming Properties after Drying] The foaming properties of the zipper fabrics produced above were evaluated using the following method. The surface of the resulting adhesive layer was visually inspected to confirm the foaming state. The evaluation criteria were as follows. The results are shown in Table 2. Good: No swelling due to foaming was observed on the surface layer film. Unacceptable: One or more swellings due to foaming were observed on the surface layer film.

[Table 2] Performance Evaluation Processability of adhesives Test number Acetone resistance test Reciprocating opening and closing durability test in normal temperature and humidity environment (500 times) Reciprocating opening and closing durability test at normal temperature and humidity (1000 times) Reciprocating opening and closing durability test in normal temperature and humidity environment (1500 times) Reciprocating opening and closing durability test in normal temperature and humidity environment (2000 times) Reciprocating opening and closing durability test in high temperature and high humidity environment (100 times) thrombocytopenia Leveling Foaming properties after drying A B 1 A C C C C C D good good good 2 A C C C C C C good good good 3 A B B B B B B good good good 4 A A A A A A A good good good

(Discussion) Based on the test results of various zipper fabrics from various test numbers, it was confirmed that water-based polyurethane produced by the acetone method can provide excellent adhesion between the waterproof membrane and the base fabric of zipper fabrics, and also exhibits excellent chemical resistance. Furthermore, the preferred embodiments (Tests 3 and 4) demonstrated even better chemical resistance and excellent reciprocating durability when used in zippers.

10: Zipper fabric 11: Base fabric 12: Waterproof membrane 13: Surface layer 14: Adhesive layer 20: Waterproof zipper 21: Chain teeth 22: Slide 23: Core cord 24: Seam thread 25: Pull tab 26: Top stop 27: Zipper strap 28: Zipper teeth 29: Slide 30: Zipper fabric 31: Core 32: Base fabric 33: Waterproof membrane

Figure 1 is a schematic diagram illustrating the layered structure of the zipper fabric of a zipper according to one embodiment of the present invention. Figure 2 is a top view of the zipper according to one embodiment of the present invention. Figure 3 is a cross-sectional view of the zipper according to one embodiment of the present invention. Figure 4 is a perspective cross-sectional view of the zipper according to one embodiment of the present invention. Figure 5 is a perspective view of the zipper tape constituting the zipper according to another embodiment of the present invention. Figure 6 is a cross-sectional view of the zipper shown in Figure 5.

10: Zipper fabric

11: Base fabric

12:Waterstop film

13: Epidermis

14: Next layer

Claims (13)

A zipper chain fabric (10) comprises a base fabric (11, 32) and a water-stop film (12, 33) attached to at least one side of the base fabric (11, 32), wherein the water-stop film (12, 33) has a layered structure comprising: a surface layer (13) comprising a film made of water-based polyurethane produced by an acetone method; and a bonding layer (14) adjacent to the surface layer (13) and comprising a cured product containing a bonding agent of water-based polyurethane produced by an acetone method. In the zipper fabric of claim 1, the water-based polyurethane used as the raw material of the membrane and the water-based polyurethane contained in the adhesive both contain polycarbonate-based polyurethane. The zipper chain fabric of claim 1 or 2, wherein the adhesive is a two-component adhesive, which is hardened by mixing at least a water-based polyurethane having a hydroxyl group produced by an acetone method as a main agent and an isocyanate compound as a hardener. The zipper fabric of claim 3, wherein the water-based polyurethane having a hydroxyl group produced by the acetone method as a main agent contains a polycarbonate-based polyurethane having a hydroxyl group. The zipper chain fabric of claim 4, wherein the cured product of the adhesive is obtained by mixing at least a base agent and a curing agent such that the molar ratio (NCO/OH) of the isocyanate group (NCO) of the isocyanate compound serving as the curing agent to the hydroxyl group (OH) of the water-based polyurethane serving as the base agent is 1.4 or greater. The zipper fabric of any one of claims 1 to 5, wherein the water-based polyurethane used as a raw material for the above-mentioned membrane and produced by the acetone method is obtained by mixing a low molecular weight water-based polyurethane with a weight average molecular weight of 7,000 to 15,000 and a high molecular weight water-based polyurethane with a weight average molecular weight of 18,000 to 32,000 in a mass ratio of low molecular weight water-based polyurethane:high molecular weight water-based polyurethane = 5:95 to 20:80. A zipper comprising the zipper fabric according to any one of claims 1 to 6. A method for manufacturing a zipper chain fabric comprises the following steps: Adhering a skin layer (13) comprising a film made of water-based polyurethane produced by an acetone method to a base fabric (11, 32) via an adhesive containing water-based polyurethane produced by an acetone method; and Curing the adhesive sandwiched between the skin layer (13) and the base fabric (11, 32). In the method for manufacturing a zipper fabric as claimed in claim 8, the water-based polyurethane used as a raw material for the above-mentioned film and the water-based polyurethane contained in the above-mentioned adhesive both contain polycarbonate-based polyurethane. The method for manufacturing a zipper fabric according to claim 8 or 9, wherein the adhesive is a two-component adhesive that is hardened by mixing at least a water-based polyurethane having a hydroxyl group produced by an acetone method as a main agent and an isocyanate compound as a hardener. The method for manufacturing a zipper fabric as claimed in claim 10, wherein the water-based polyurethane having a hydroxyl group produced by the acetone method as a main agent contains a polycarbonate-based polyurethane having a hydroxyl group. The method for manufacturing a zipper fabric according to claim 11, wherein the cured adhesive is obtained by mixing at least a base agent and a curing agent such that the molar ratio (NCO/OH) of the isocyanate group (NCO) of the isocyanate compound serving as the curing agent to the hydroxyl group (OH) of the water-based polyurethane serving as the base agent is 1.4 or greater. A method for manufacturing a zipper fabric as claimed in any one of claims 8 to 12, wherein the water-based polyurethane adhesive used as a raw material for the above-mentioned membrane and produced by the acetone method is obtained by mixing a low molecular weight water-based polyurethane with a weight average molecular weight of 7,000 to 15,000 and a high molecular weight water-based polyurethane with a weight average molecular weight of 18,000 to 32,000 in a mass ratio of low molecular weight water-based polyurethane:high molecular weight water-based polyurethane = 5:95 to 20:80.